1. Field of Invention
The present invention relates to a manufacturing method for a semiconductor device and more particularly to the treatment of the aluminum interconnecting layer after etching.
2. Description of the Related Art
Conventionally, the fixed pattern of the interconnecting layer is formed through using a resist along with gases such as BCl.sub.3, Cl.sub.2 and the like, after which the resist layer is washed away in oxygen gas at a standard temperature of about 40.degree. C. Then, the residual chlorine is washed away with water and corrosion of the interconnecting layer by the chlorine is prevented.
In the conventional processing method mentioned above, there are problems whereby; the residual chlorine cannot be completely removed, the interconnecting layer is corroded before the water washing treatment, and some residual silicon still remains on the aluminum alloy interconnecting layer even after etching.
Furthermore, the problem with the dry etching after treatment of the aforementioned interconnecting layer is that a sidewall protection layer which is formed in the dry etching process is remoed.
The sidewall protection layer is a kind of protection layer which is formed on the sidewall of the layer to be etched during a step of the anisotropic etching of the interconnecting layer.
This protection layer is thought to have accumulated on the sidewall of the layer to be etched as a product of reactions between radicals in the plasma generated simultaneously with the etching reaction.
In the publication, "JAPANESE JOURNAL OF APPLIED PHYSICS, Vol.19, No.7, July 1980 (pp. L405-L408)", it is proposed that the sidewall protection layer is composed of polymerized organic matter which has separated from the photoresist.
As a result of this sidewall protection layer being formed, undercutting of the layer to be etched is prevented, thus giving a construction where there is anisotropic etching in the vertical direction.
However, even when the sidewall protection layer is still intact after dry etching there are still a number of problems. For example, chlorine remaining on the sidewall protection layer causes corrosion in the metal interconnecting layer. In addition to this, after removal of the photoresist an acute sidewall protection layer still remains on the side of the etched layer and this causes damage to any additional layers formed on top of this layer at later stages.